(Solved) Indigo Alpha Lens focus issue

[Bill W]

Hi Sam.

No glue, no grub screws.  Through the small side holes I can see the rear of the lens body move past the holes.  Could be that if those are holes for grub screws then they would need to be fully removed to allow infinity focus

regards
Bill

[Fraser]

Bill has provided what we needed to know. His lens mount is indeed the same as the your recalcitrant lens Sam.

If it were my camera I would now take a major, if somewhat brutal, step. I would mount the whole camera in a soft jaw vice ensuring that the lens mount front panel is also gripped tight. I would then wrap the lens barrel in a grippy material like rubber, neoprene or layers of electrical tape. Now the nasty bit. I would us a pipe wrench, yes I know it is an awfully thought,  and gently grip the lens barrel via the protective material already applied. I would the rock the barrel back and forth gently before applying more torque in the counter clockwise direction. Some common sense is needed on how much force is applied as you do not want to cause distortion of the aluminium. With luck the lens will free off.

For info, the pipe wrench I would use is like a pair of pliers with long handles and a 45 Degree angled head with a nice scolopped jaw to grip pipes. They are not a Stilson wrench !

Fraser

[Bill W]

Just had a close look at one of your images Sam, and there's two odd looking blobs inside the lens which I have arrowed.  they do not look right and might be what is locking it up.
See attached

regards
Bill

[sam1275]

Hi Sam.

No glue, no grub screws.  Through the small side holes I can see the rear of the lens body move past the holes.  Could be that if those are holes for grub screws then they would need to be fully removed to allow infinity focus

regards
Bill

Thank you, mine also have no grub screws, in the previous post I meant the grub it self.
I can also see the rear of the lens body through the holes.

[sam1275]

Bill has provided what we needed to know. His lens mount is indeed the same as the your recalcitrant lens Sam.

If it were my camera I would now take a major, if somewhat brutal, step. I would mount the whole camera in a soft jaw vice ensuring that the lens mount front panel is also gripped tight. I would then wrap the lens barrel in a grippy material like rubber, neoprene or layers of electrical tape. Now the nasty bit. I would us a pipe wrench, yes I know it is an awfully thought,  and gently grip the lens barrel via the protective material already applied. I would the rock the barrel back and forth gently before applying more torque in the counter clockwise direction. Some common sense is needed on how much force is applied as you do not want to cause distortion of the aluminium. With luck the lens will free off.

For info, the pipe wrench I would use is like a pair of pliers with long handles and a 45 Degree angled head with a nice scolopped jaw to grip pipes. They are not a Stilson wrench !

Fraser

Thank you, I don't have those tools now, maybe I have to buy them if necessary, BTW, should I really try force it before I deal with the glue?

[sam1275]

Just had a close look at one of your images Sam, and there's two odd looking blobs inside the lens which I have arrowed.  they do not look right and might be what is locking it up.
See attached

regards
Bill

Hi Bill, I rechecked my camera, what you pointed in the picture is not any additional parts, they are just full circles of glues.

[Fraser]

Sam,

If the lens is locked by just a small blob of glue it will likely shear under force and release the lens thread. If the glue is all around the circumference of the lens thread then sadly the glue will have a lot of active surface and is unlikely to release the thread

You asked about using suitable solvents to soften the glue.

Without knowing the type of glue this will be a case of experimentation. My concerns are as follows...... If the glue was just in one spot, using solvent could cause it to flow into the threads potentially making the situation worse. Some solvents could cause damage to the lens elements if it gets on them. If you go down the solvent path you have to soften the glue and then remove it all before the solvent evaporates and the glue hardens again.

In such a case I would normally remove the lens assembly from the camera (including front panel in your case) with the intention to completely strip it down on the bench for cleaning and rebuild. You have the added complication of the FFC shutter/iris assembly. No contaminants should come into contact with the FFC shutter/iris.

If possible cut away a small sample of the glue with a sharp hobby knife. You will test the solvents on this sample and so protect the lens assembly from risk during such tests.

In terms of potential solvents I always start with the least aggressive. I would see what IPA does first, then white spirit, then methylated spirit followed by acetone. Acetone is pretty aggressive and desolves many plastics. A really aggressive solvent is liquid paint stripper but this should be used with extreme caution as it can damage many things, including you ! It can desolve many glues however. Test your solvents on the small sample of glue in a jar to see what effect, if any, it has upon it. You want the solvent to liquify the sample. I suspect IPA, white spirit and methylated spirits  will fail. Acetone has a good chance of dissolving the glue and paint stripper is so aggressive that it will also likely dissolve the glue.

I do not envy you doing this task. I would rate it as a pretty miserable situation with not insignificant risk to the lens assembly.

Best Wishes

Fraser

[Bill W]

The only positive is that the lens has a big square flange to fit in a vice, and the part that should move has the grip on it.

One other thought, heat ?  Again depends on what the glue is and if you can get any out to test.

Best of luck

Bill

[sam1275]

Thank you everyone, I really appreciate your help. I seem to be a little unlucky on this, however I'll try to solve it, I'm not good at chemistry so the solvents Fraser given is a big help. I'll report here if there's any progress.

[sam1275]

Hello everyone, I just solved the problem.
I bought the tools and ready to do the "brutal" method provided by Fraser, but I thought I should have a last try before it, so I used all my strength to turn the lens bare handed, and it moves
So it turns out that the cause is very simple, the lens was over-tightened on the counter-clock wise, thus locked it to the nearest focus distance, and it just need a strong arm.
Sorry that I over-sighted the problem and create such a long mess thread...
However I'm glad I use the least harmful method to solve it, especially didn't use chemical, because I took it apart again after I loose the lens, I found the whole thing will rotate together, so I think the glues supposed to glue the individual lens together to a lens module, I would destroy the lens module structure if I unglue them.
Thank you everyone for your help!

[Bill W]

Great news to hear another camera is back from the dead

 

Bill

[Fraser]

Excellent news Sam. Mystery solved 🙂👍

[sam1275]

Thank you all.
I found a weird thing on my Indigo Alpha, it seems to perform NUC purely based on time, and unaware of temperature.
It will NUC 6 times on startup (including the initial one) with 10 seconds interval, then it will do NUC every 2 minutes.
Does the Alpha suppose like this?

[Fraser]

When the camera initially starts it carries out a number of FFC events for initial calibration of the image. The microbolometer temperature is being raised to 32C by the TEC during that time. After that the FFC events are fixed in the configuration settings at 120 second intervals. This is considered adequate to correct for nominal pixel drift. IIRC the interval between FDC events may be set in the cameras configuration and it can even be switched off for video recording applications where an FFC event is undesirable. This is certainly the case with the TAU anyway. Take a look at the Alpha user manual, it should detail FFC period and any configuration options. On some cameras an FFC event is triggered when the camera detects temperature changes that need an FFC to ensure a flat field. Not sure about the Alpha though.

Fraser

[sam1275]

Hello Fraser.
I forgot those cameras have a active temperature stabilization, instead the only temperature monitoring in modern TICs.
I re-read the Alpha manual again and it mentioned it have temperature sensors for both FPA and case, but it didn't say FFC will act according to those.
I didn't read the manual carefully before, I just found it can operate at 5-30v. Also the digital interface pin out and commands are documented, but I have a few more questions:
It says it's RS232 compatible but operate at 3v, it's very strange because RS232 should operate at +-13v, and those 3.3v TTL are inverted RS232 levels, so how can I communicate?
Does the settings persistent through power cycles?
Thank you.

[Fraser]

Sam,

Go back to the thread where we were identifying your Alpha. In that thread I explained the Communications link and referenced my work on a TAU core that uses the same hardware levels.

The Communications are serial and in common RS232 format but the levels are not true RS232. It is UART 'RS232' meaning the levels are 0v and 3v3 with a Space being 0v and Mark being +3v3. Common Maxim UART to true RS232 levels are inverting and produce the required negative Mark and positive Space levels as per the RS232 standard.

I used a USB to UART serial board fron China. The board takes its power from the 5V USB supply and provides a 5V and 3v3 output for accessory use. I powered a simple 74HC series inverter chip from the 3v3 and inverted the data inputs and outputs of the USB/UART board. I understand that FTDI USB/UART boards have the option to invert the output via a configuration setting but I was not using FTDI.

Hope this helps a little.

Fraser

[sam1275]

Sam,

Go back to the thread where we were identifying your Alpha. In that thread I explained the Communications link and referenced my work on a TAU core that uses the same hardware levels.

The Communications are serial and in common RS232 format but the levels are not true RS232. It is UART 'RS232' meaning the levels are 0v and 3v3 with a Space being 0v and Mark being +3v3. Common Maxim UART to true RS232 levels are inverting and produce the required negative Mark and positive Space levels as per the RS232 standard.

I used a USB to UART serial board fron China. The board takes its power from the 5V USB supply and provides a 5V and 3v3 output for accessory use. I powered a simple 74HC series inverter chip from the 3v3 and inverted the data inputs and outputs of the USB/UART board. I understand that FTDI USB/UART boards have the option to invert the output via a configuration setting but I was not using FTDI.

Hope this helps a little.

Fraser

Thank you very much, I actually read your post before, however I was not sure it's the same situation as mine at that time.
I used my beaglebone black for serial host, I think maybe I could find a way to make the software invert the level somehow.
Would you mind tell me if the settings persist through power cycle?

[Fraser]

Hi Sam,

Yes the settings persist until changed by the configuration software. They are stored in non volatile memory.

Fraser

[sam1275]

Hi Sam,

Yes the settings persist until changed by the configuration software. They are stored in non volatile memory.

Fraser

Thank you Fraser!